Neural Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells: Applicability for Inner Ear Therapy

BACKGROUND AND OBJECTIVES: Regeneration or replacement of damaged hair cells and neurons in the cochlea might be an ideal treatment for sensorineural hearing loss (SNHL). The purpose of the present study was to investigate whether mesenchymal stem cells (MSCs), derived from the bone marrow of rats, could differentiate into auditory hair cells and neurons. MATERIALS AND METHODS: The centrifuge gradient method was used to isolate MSCs from the bone marrow of rats. To confirm whether bone marrow-derived MSCs can differentiate into neuronal cells, culture medium with glial cell-derived neurotrophic factor, brain-derived neurotrophic factor and neurotrophin-3 for 14 days. In addition, immunofluorescence staining and RT-PCR were performed for characterization of the neurospheres and differentiated cells from 7 and 14 day cultures. RESULTS: The results showed that MSCs could differentiate into neuron-positive and hair cell-positive cells, using different compositions of growth factors. And RT-PCR result was identified high or low of gene expression all these differentiated cells. CONCLUSIONS: Rat bone marrow-derived MSCs differentiated into neuronal progenitor cells. These cells might be useful for the treatment of SNHL.

Effect of Growth Factors on Hearing Restoration in Deafened Animal Model / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Sensorineural hearing loss is caused by ototoxic drugs, radiation therapy, noise exposure and trauma, etc. They make irreversible changes in cochlear hair cells and degeneration of spiral ganglion neurons. It is known that neurotrophins and other growth factors have an important role in protectingcochlear hair cells and spiral ganglion neurons. We designed this study to analyze the effect of neurotrophins and growth factors delivered to the inner ear of deafened guinea pig. MATERIALS AND METHOD: Healthy 15 guinea pigs with normal Preyer's reflex were chosen, and were made deaf by infusion of kanamycin and ethacrynic acid. Myringotomy was done to both ears, normal saline injected into the left ear, and BDNF (brainderived neurotrophic factor), GDNF (glial cell derived neurotrophic factor), NT-3 (neurotrophin-3), IGF (insulin-like growth factor), EGF (epidermal growth factor), FGF (fibroblast growth factor) were injected in the right ear. RESULTS: Statistically significant hearing gain was obtained up to 35.00+/-13.78 dB in the group 1 (BDNF, GDNF, NT-3 treated group), and up to 34.0+/-5.47 dB in the group 2 (IGF treated group). However, no statistically significant hearing gain was observed in the group 3 (EGF, FGF treated group). CONCLUSION: We observed statistically important improvement of hearing threshold in the BDNF, GDNF, NT-3 treated group and IGF treated group.

Unusual Prolonged Recovery of Succinylcholine - induced Neuromuscular Block Following Neostigmin / 대한마취과학회지

We report a case of slow recovery of the neuromuscular block induced by succinylcholine (SCC) immediately after administration of neostigmine for the reversal of pancuronium. Left hemithyroidectomy was performed in a 4l kg female patient under general endotracheal inhalation anesthesia with 50%-nitrous oxide and 2.0%-enflurane. Four mg of pancuronium was used for muscular relaxation to facilitate the controlled ventilaion on the anesthesia ventilator. At the end of the operation, one and a half hours from the injection of pancuronium, 10 mg of pyridostigmine was administered to reverse the neuromuscular blockade. Five minutes later, 25 mg of succinylcholine was given for reintubation. Following this event, train-of-four stimuli was applied under the uncalibrated mode with Datex Relaxograph because apnea followed by SCC appeared for more than 30 minutes. Neuromuscular monitoring revealed fade to less than 50% of the T, ratio. The ventilator was applied for the recovery of neuromuscular blockade for one hour. There was no more late complications after transfer to the ward. The literature relating to this iatrogenic complication and phase II block after SCC is reviewed and discussed.